Measuring Receiver
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Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

, a measuring receiver or measurement receiver is a calibrated laboratory-grade radio receiver designed to measure the characteristics of radio signals. The parameters of such receivers (tuning frequency, receiving bandwidth, gain) can usually be adjusted over a much wider range of values than is the case with other radio receivers. Their circuitry is optimized for stability and to enable calibration and reproducible results. Some measurement receivers also have especially robust input circuits that can survive brief impulses of more than 1000 V, as they can occur during measurements of radio signals on power lines and other conductors.

Applications

Measuring receivers are used with calibrated antennas to
  • determine the signal-strength and standards-compliance of broadcast signals,
  • investigate and quantify radio-frequency interference,
  • determine compliance of a device with electromagnetic interference
    Electromagnetic interference
    Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...

     and TEMPEST
    TEMPEST
    TEMPEST is a codename referring to investigations and studies of compromising emission . Compromising emanations are defined as unintentional intelligence-bearing signals which, if intercepted and analyzed, may disclose the information transmitted, received, handled, or otherwise processed by any...

     standards and regulations.


Measuring receivers are also used without antennas to
  • calibrate RF
    Radio frequency
    Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...

     attenuators and signal generator
    Signal generator
    Signal generators, also known variously as function generators, RF and microwave signal generators, pitch generators, arbitrary waveform generators, digital pattern generators or frequency generators are electronic devices that generate repeating or non-repeating electronic signals...

    s.


Measuring receivers are widely used in metrology and calibration lab environments, spectrum monitoring and electromagnetic-compatibility facilities.

Types

Depending on the intended application area, several types of measuring receivers can be distinguished:
  • Spectrum analyzer
    Spectrum analyzer
    A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals...

    s
    are intended to graphically display the amplitude spectrum of a radio signal on a logarithmic scale.

  • Modulation analyzers are intended to accurately measure not only the signal power level, but also the degree of modulation (such as AM
    Amplitude modulation
    Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...

     depth, FM/PM deviations), and modulation distortions.

  • EMI receivers are designed to comply with the detailed equipment requirements of measurement standards for radio interference, such as the civilian specification CISPR 16-1-1 or the military specification MIL-STD-461. The EMI receiver has defined IF-Bandwidths (typically 200 Hz, 9 kHz, 120 kHz, 1 MHz) and standardized detector modes (peak, quasipeak, average, rms, CISPR-AV and CISPR-RMS, RMS-Average). They use a preselection for an improved dynamic range. Rohde & Schwarz
    Rohde & Schwarz
    Rohde & Schwarz is an independent group of companies specializing in electronics. Well known as a manufacturer of electronic test equipment, they also manufacture equipment used for broadcasting, radiolocation, and radio communications...

     holds the patent for RMS-Average Detector which is important to be compliant to CISPR 16-1-1.

  • Time-domain EMI Measurement systems are systems that perform a baseband sampling and simulate all the IF-Bandwidths and detectors digitally. Typically this is done via Short Time Fast Fourier Transform (STFFT). Such measurement systems emulate several thousand EMI receivers digitally in parallel. The most advanced instruments allow to speed up the measurement by a factor of 4000. Measurements can be performed according to the standards CISPR 16-1-1, MIL461 and DO160. The benefit are extremely fast measurements.

  • TEMPEST
    TEMPEST
    TEMPEST is a codename referring to investigations and studies of compromising emission . Compromising emanations are defined as unintentional intelligence-bearing signals which, if intercepted and analyzed, may disclose the information transmitted, received, handled, or otherwise processed by any...

     receivers
    are designed to comply with the requirements of measurement standards for compromising-emanations such as SDIP-27 or NSTISSAM TEMPEST/1-92. For example, their frequency range extends down to acoustic frequencies (typically 100 Hz), their bandwidth can be adjusted in 1-2-5 steps from a few hertz
    Hertz
    The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

     to more than 100 MHz, and their sensitivity and noise figure
    Noise figure
    Noise figure is a measure of degradation of the signal-to-noise ratio , caused by components in a radio frequency signal chain. The noise figure is defined as the ratio of the output noise power of a device to the portion thereof attributable to thermal noise in the input termination at standard...

     aims to be close to what is technically feasible.


Some measuring receivers (such as Rohde & Schwarz
Rohde & Schwarz
Rohde & Schwarz is an independent group of companies specializing in electronics. Well known as a manufacturer of electronic test equipment, they also manufacture equipment used for broadcasting, radiolocation, and radio communications...

's FSMR, ESU or Agilent’s N5531S) also include a signal analyzer, power meter, and a sensor module to allow the instruments to be used together or individually for general-purpose measurement tasks.

The time-domain EMI measurement systems TDEMI of GAUSS INSTRUMENTS show additional features like weighted spectrogram mode, oscilloscope mode as well as measurement of discontinuous disturbance according to CISPR 14-1.

Manufacturers and products

  • Agilent
  • Anritsu
    Anritsu
    is a Japanese corporation that is in the test and measurement market. Products include microwave, RF, and optical signal generators , spectrum analyzers, and network analyzers. It was formed with the merger of two companies, the Annaka Corporation and Kyoritsu Electric in Japan in 1931. In 1990...

  • CRFS Limited
  • Dynamic Sciences International, Inc. [www.dynamicsciences.com]
    • DSI-450 and DSI-600 EMI test receivers
    • R-110B Survellance Receiver and R-1550-A TEMPEST test receivers
  • Electro-Metrics
  • GAUSS INSTRUMENTS GmbH, www.gauss-instruments.com
    • TDEMI 30M, TDEMI 1G, TDEMI 3G, TDEMI 18G, TDEMI 26G for measurements according to CISPR and MIL/DO
  • Narda Safety Test Solutions
    • PMM 9010-9060 EMC/EMI test receivers.
  • Rohde & Schwarz
    Rohde & Schwarz
    Rohde & Schwarz is an independent group of companies specializing in electronics. Well known as a manufacturer of electronic test equipment, they also manufacture equipment used for broadcasting, radiolocation, and radio communications...

    • FSG and FMx series signal and modulation analyzers
    • ESU, ESIB, and ESCI measuring receivers for EMC and field-strength measurements
    • FSET series TEMPEST preselectors, spectrum analyzers and measuring receivers
  • Teseq
    • SMR, SCR measureing receiver series for EMC measurements

External links

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